<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2013-06-27</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000728385</issuerCik>
        <issuerName>Midwest Energy Emissions Corp.</issuerName>
        <issuerTradingSymbol>MEEC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001524386</rptOwnerCik>
            <rptOwnerName>MacPherson Richard</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>34 CEDARBANK TERRACE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>HALIFAX</rptOwnerCity>
            <rptOwnerState>A5</rptOwnerState>
            <rptOwnerZipCode>B3P 2TR</rptOwnerZipCode>
            <rptOwnerStateDescription>NOVA SCOTIA, CANADA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>12% Convertible Promissory Notes</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.5</value>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2013-06-27</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionTotalValue>
                    <value>614012</value>
                </transactionTotalValue>
                <transactionPricePerShare>
                    <value>614012</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2013-06-27</value>
            </exerciseDate>
            <expirationDate>
                <value>2016-06-27</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Units</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <footnoteId id="F1"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>614012</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By 3253517 Nova Scotia Limited</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>12% Convertible Promissory Notes</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.5</value>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2013-06-27</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionTotalValue>
                    <value>252199</value>
                </transactionTotalValue>
                <transactionPricePerShare>
                    <value>252199</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2013-06-27</value>
            </exerciseDate>
            <expirationDate>
                <value>2016-06-27</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Units</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <footnoteId id="F1"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>252199</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Pursuant to a Conversion Agreement entered into with the Issuer, the Issuer converted advances payable from the Reporting Person into Convertible Notes of the Issuer. Each Convertible Note is convertible into Units of the Issuer at a conversion price of $0.50 per Unit with each Unit consisting of one share of common stock of the Issuer and one warrant to purchase 0.25 additional shares of common stock at $0.75 per share.</footnote>
        <footnote id="F2">The Reporting Person is the controlling principal of 3253517 Nova Scotia Limited.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Richard MacPherson</signatureName>
        <signatureDate>2013-07-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
